x1, y1, x2, y2 = [float(n) for n in input().split()]
print(((x2-x1)**2+(y2-y1)**2)**0.5)
 float(n) for n in input().split() for n in input().split() n input().split() ().split () input split for n in input().split() float(n) float n x1, y1, x2, y2 = [float(n) for n in input().split()] x1 [float(n) for n in input().split()] y1 x2 y2 print(((x2-x1)**2+(y2-y1)**2)**0.5) print ((x2-x1)**2+(y2-y1)**2)**0.5 (x2-x1)**2+(y2-y1)**2 (x2-x1)**2 x2-x1 x2 x1 2 (y2-y1)**2 y2-y1 y2 y1 2 0.5 y2 = [float(n) for n in input().split()] [float(n) for n in input().split()] y2 x1, y1, x2, y2 = [float(n) for n in input().split()] [float(n) for n in input().split()] x1 y1, x2, y2 = [float(n) for n in input().split()] [float(n) for n in input().split()] y1 x2, y2 = [float(n) for n in input().split()] [float(n) for n in input().split()] x2
x1, y1, x2, y2 = [float(n) for n in input().split()]
print(((x2-x1)**2+(y2-y1)**2)**0.5)

